looking for sister born 57 or 58?

I was born 2/4/1957 - Washington D.C. and was adopted from St. Ann's Infant & Maternity Home in Maryland. Born in Providence Hospital. Birth Name Tracy Ann, Adopted name is Joan. I do not have any given name for mother but she would have been about 20 yrs. old at time and was told "identifying information" she was blond with blue eyes. I am not sure this is reliable. please reply if this may be helpful to you or me! thanks. Joan